1. Field of the Invention
The invention relates generally to the manufacture of molded building products, and more particularly to dies used to manufacture molded door facings that include sharp convex corners, such as facings that may be attached to a frame to create a six-panel door.
2. Description of Related Technology
It is known that an approximately 1/8" thick door facing can be molded by compressing an approximately 3/4" to 1" thick rigid fiberboard mat between matched front- and back-side dies.
In making such a facing, the front-side die carries the desired profile of the door and any desired grain pattern. The back-side die has been traditionally configured to provide equal density consolidation of the fiberboard mat throughout the facing. Equal consolidation has been found to be desirable because two similar portions of the facing consolidated unequally will generally have different physical characteristics.
In cases where the desired profile of the facing does not have steeply-slanted surfaces, nearly equal consolidation of the mat throughout the facing can be obtained by matching the profile of back-side die nearly exactly to the profile of the front-side die.
In cases where the desired profile of the facing does have steeply-slanted surfaces, back-side dies are sometimes designed with minor planar offsets in starting points or end points for the slanted surfaces. These offsets result in a slight decrease in the degree of consolidation of the fiberboard mat in the slanted surfaces, but are thought to be necessary to help assure that there is enough material in the slanted surface to provide necessary strength. (The need for offsets can be understood by considering the result if a facing was designed with a surface slanted at 90.degree.. A back-side die with exactly the same profile as the front-side die would shear the product at the 90.degree. surface.)
There has been a consistent problem in achieving high fidelity of the front side of a facing to the front-side die, particularly in areas corresponding to convex corners in the desired profile. When sharp convex corners are incorporated into a die, it is common that the molded facings do not faithfully reproduce the desired corner, but instead tend to have a rounded, "soft" corner. Thus, it has been difficult to convincingly reproduce the appearance of a natural wood six-panel door or other natural wood door having sharp convex corners in a door made from molded facings.